Toganga Colombia four people stung by 1 jelly

The jelly was found and caught in about 2>3 feet of water. The bell was approx 3 inches wide and 4 to 5 inches long, it appeared rectangular and flat when out of the sea held up by the bell. Looked like a plastic bag at a glance. Tenticals were semi transparent, circa 8+ inches long and a rose color almost vain like something running down the length of the tentacles. Sting burning sensation then more like a wasp sting then later returning to a burning sensation. multiple stings on both legs still burning after 12 hours. 5 people stung in about 3 to 4 minuets. Local people found it and caught it.